Spark plug



Nov.14, 1939. J. P. KLETZ 2,180,242

SPARK FLUG Filed Feb. 17, 1939 Patented Nov. 14, 1939 UNITED STATES PATET OFFICE 4 Claims.

The invention relates to a spark plug and mo1e especially 110 an air and liquid cooled spark plug With e1ectrical r-eplacement parts.

The primary object of the invention is the provision f a spark plug of this character, wherein the main body 01 shel1 and the insulator associated therewith is externally finned 130 assure, in the operation of the plug, the cooling therebf, while the electrical parts of saic1 p1ug are readily separable from each other for replacement purposes.

Another object of the invention is the p-rovision of a spark plug of Izhis character, wherein o-ne 0f the electrodes is fitted thereto in a novel manner 130 reguiate its association With the other electrode fsr proper spark gapping of the same.

A further object of the invention is the provision of a spark: p1ug of this character, wherein the parts are assembled in a unique manner, g'iving longevity to the plug anal minimizing breakage as weil as enabling replacement of said parts With dispatch.

A still further object of the invention is the provision of a spark plug of this character, which is simple in its construction, thoroughly reliable and efficient in operation, easy of repairs, streng, durable, anti inexpensive to manufacture.

With these and other objects in view, the invention consis'ts in the features of construction, combination and arrangement of parts as Will be hereinafter more fu1ly described, illustrated in t;he accompanying drawing, which discloses the preferred embodiment of the invention and pointed out in the c1aims hereunto appended.

In the accompanying drawing:

Figure 1 is an elevation of a spark plug comstructed in accordance with the invention.

Figure 2 is a vertical longitudinal sectional view thereof.

Figure 3 is a bottom plan view.

Similar reference characcers indicate corresponding parts throughout the severa1 views in the drawing.

Referring to the drawing in detail, the spark plug constructed in accordance With the invention cemprises a body I0 constituting the metai shell having an externally threaded annular skirt end for the creation 0f a nipple II so that this body can be associated with an internal combustion engine and arranged in the ignition system of a motor vehicle, as usua1, being preferably tapped into a hole f01 the plug in the head of the block of such engine. The body II) uppermost With relation to the skirted end II is externally peripherally finned a1; I2 and these fins are square-faced, as a1: I3, so that the body II) can be screwed into its seating conveniently. The fins are spaced from each othe1 in a vertical direction.

Internally cf the body III is a circular 1edge I 4 forming a shoulder 0r seat f0r an insulator I5 of tubular construction, having the lower downwardly tapered rmer end I6 while the uppermost portion o1 this insulator is of approximately uniform circular contour in cross section and. said portion carries externally ther'eof annular fins I'I, these being vertically spaced from each other, as is shown in Figures 1 and 2 0f the drawing.

The insulator I5 is he1d seated by a nut I8 having a center clearance for the said insulator and is separably threaded into the upper end of the body III. The nut I8, as usual, is flat-faced for wrench engag-ement therewith so that iI3 can be separably fastened in the b-ody. The insula tor has associated therewith suitable gaskets I9 and 20, respeccively.

Fitted centrally in the insulator I5 is the main electrode 2I while built at the edge 0f the skirt end II is a bcss 22. This boss has fitted therein a set screw 23 engageable with an auxiliary electrode 24, being slidably fitted in inwardly sloping relation to the main e1ectrode 2I in a, guideway 25 formed in said skirt end II of the body III. The adjustment of the eiectrode 24 With respect to the electrode 2I regulates the sparking gap. The way 25 is squared correspondingly to the squar6d cross sectional form of the auxiliary electrode 24.

The main e1ectrode 2I is he1d fitted in the insu1ator I5 by a nut 26 seating a cap 21 which surrounds said electrode and engages With the uppermost end 0I" the insulator I5.

It is preferable that the main electrode 2I be squared in cross section for a distance thereof and this portion is seated in a correspondingly shaped clearance, thus holding the said electrode against rotation in the insulator I5. The set screw 23 is accessible when the plug has been removed 01' detached from the engine so that accuracy may be assured in the spark gapping of. the said electrocles 2I and 24.

By reason of I:he construction of the spark plug, the e1ectrical ancl other parts thereof are susceptible 01 convenient replacement as the occasion may require.

The cap 21 in association With the main e1ectrode 2I and also the nut 26 enab-les electrical connection 0f the plug With the ignition system of the motor.

The tapered end I6 of the insulator I5 extends Within the hollow center 28 01 the boc1y I0, as shown in Figure 2 of the drawing.

The sparking lower end of the main electrode 24 is preferably squared in cross section and in conformity with the squared cross sectional formation of Ehe auxiliary electrode 24.

What is claimed is:

1. A spark plug of the Kind described comprising an externally finned plug bocly having a skirt portion threaded exteriorly .fcr a portion of its length, a thickened extension 011 the skirt ab one side thereof below tne threads and having an inwardly sloping aperture extending diagona1ly downwardly therethrough, a tubiform insulator interfitting the said plug body and having external annular fins above said body, a main electrode arranged centrally of said insulator anal protruding into the plug body, a second electrocle slidably fitting the aperture in the tnickened extension .for adjustment toward anal away from the main electrode, anc1 means engaged in said tnickened extension for fastening the sesond elecsrode in adjusted positic-n and accessible at the inne1 end of the plug' body.

2. A spark p1ug of the Kind described cum-- prising an externally finned plug body having a skirt portion threaded exteriorly fo1 a portion of its length, a thickened extension on the skirt ab one side thereof below tne threads anal having an inwardly sloping aperture extending diagonal1y downwardly therethrough, a tubiform insulator interfitting the said p1ug body and having externa1 annular fins above saicl body, a main electrode arranged centrally of said insulator and protruding into the p1ug body, a second electrode slid.ably fitting t'ne aperture in the thickened extension for aajustment toward and away from the main electrode, means engaged in said thickened extension for fastening alle S- ond. electrode in adjusted position and accessible at the inner end of the plug body, and a locking nut threaded in the outer end 0f said plug body for removably fastening the insulacor interfitted. with said body.

3. A spark plug of the kind. described. comprising an externally finned plug body having a skirt portion threaded exteriorly for a portion of its length, a thickened extension on the skirt ab one side thereof below the threa ds and. having an inwardly sloping aperture extending diagonally downwardly therethrough, a tubiform insula'tor interfitting Ehe said p1ug body and having external annular fins above said body, a main electrode arranged centrally of said insulator anal protruding into the plug body, a second electrode slldably fitting the aperture in the thickened extension for adjustment toward and away from the main electrode, means engaged in said thickened extension for fastening the second electrode in adjustecl position and. accessible at the inner end of the plug body, a locking nut threaded in the unter end of said p1ug body for removably fastening the insulator interfitted with said body, and. a metal cap removably fitting the outer end cf the main electrode anal seated upon the outer end of said insulator.

4. A spark p1ug of the kind described comprising an externally finned plug body having a skirt portion threaded exteriorly for a portion of its length, a thic.kened extension on the skirt at one side theleof below the threads and having an inwardly sloping aperture extending diagonally downwardly therethrough, a tubiform insulator interfitoing the said plug body and having external annular fins above said body, a main electrode arranged centrally of said insulator and protruding into the p1ug body, a second electrode slidably fitoing the aperture in the thickened extension for adjustment toward and away from the main electrode, means engaged in said thickened extension for fastening the second electrorle in adjustecl position and aceessible ab the inner end 0f the plug body, a locking nut threaded in the outer end. of said p1ug body f01 removably fastening the insulator interfitted With said. body, a metal cap removably fitting the outer end of ehe main electrode and seated upon the outer end of said insulator, the mein elecbrode being of a size and cross section considerably les s than the interior cross sectional area of said insulator and an interna] seaing shoulder formed in said plug body of the said insulator.

JOSEPH P. KLETZ. 

